I had the same problem, exactly as described. O2 Broadband customer service provided the following guide to sorting it out:
“It appears like McAfee has not registered properly when you installed it. What you need to do is fully remove McAfee from your computer and install a pre registered version; this can be done through the following steps:
1. You need to remove McAfee from system. Go to the following link and run the program, it will remove McAfee and reboot computer.
http://download.mcafee.com/products/lic … s/MCPR.exe
2. Now you need to go to the following link.
3. Enter your primary O2 broadband email address and click forgot password. Enter your email address in again. this will email you out a McAfee password.
4. We need to retrieve the password from your O2 email account. Go to www.o2.co.uk and log in to web mail to retrieve password, or if you have an email program set up retrieve the password from it.
5. Go back to the McAfee login page and enter your email address and the password. The next screen will allow you to download a full pre registered version of McAfee.
If you have any questions regarding this please email or call O2 broadband customer service on 0800 230 0202, we will be happy to help.”
I hope this helps anyone in a similar situation. It worked for me.